Hardware Implementation of Transformer Step by Step

In following few paragraphs we are going to make a transformer in hardware in few easiest steps. Each Step is explained in simplest way with the help of images.

For better understandings make sure you have knowledge of basics of transformer and How to calculate design parameters of transformer. It is recommended to have a view of these articles.

Now, we have the calculated parameters we need to build the transformer. The objects you need to get for designing are:

  1. Bobbin
  2. Copper wires for primary and secondary sides of calculated gauge
  3. Laminated iron core strips (E and I)
  4. Insulation paper
  5. Winding Machine (optional)

Procedure and Instructions:

It is easiest to wind a transformer at your own with a little drill and following the easiest steps and instructions written below:

1. Prepare the Bobbin:

Prepare the Bobbin Step_1
Figure 1: Prepare Bobbin



1.  Take the bobbin and if you want to use winding machine, prepare it on the machine with suitable placement. Otherwise just check if it is clean and clear.

2. Place insulation paper to its perimeter just to make symmetric. Or else no need of insulation paper at first layer.

2. Primary Windings:

1.  Take the copper wire of primary side for winding.

2.  Leaving a little portion 6-8 inches, start the winding around the bobbin perimeter. (As shown in figure 2)

3.  Make turns of that wires by rotating the bobbin on winding machine. If you are doing it by hand you have to do some work but it is not such problem in small transformer.

4.  Each turn must be tight and very adjacent to previous turn leaving approximate no space between them. Neither has it gone overlap on previous. (figure 3)

Primary Winding_2
Figure 3: tighten the winding
Primary Start
Figure 2: Starting Primary Winding











5.  When you are done with the first layer, i.e. the complete bobbin space is filled, now move towards second layer.

6.  Write number of turns and number of layer on insulation paper after each layer just as milestone.

Primary first layer
Figure 3: One Complete Layer

7.  For second layer, place a piece (cut to inner size of bobbin) over first layer. This will serve as insulation between two layers (although wire is insulated) also it will differentiate two layers rather making jumble turns.
8.  Now, for second layer start winding the wire from the same side as the first (previous) layer was ended in the same direction but this time toward the starting point of previous layer.

9.  Complete the layers until you reach the calculated wire turns for primary. Place end point of primary winding at the same side as starting to make easy recognition of primary side. (Figure 4 Point 1) (You must count after each turn to make exact calculated number of turns). (figure 4 point 2)

Primary Winding complete
Figure 4: Complete Primary Layer

3. Secondary Windings:

1.  When you done with primary, place insulation paper and start winding secondary side wire over it. You can start winding secondary from either starting or ending side of primary (figure 5 point 1).

2.  Do the winding same as primary and make layers if necessary. Now you are done with the winding. At this time it is just two coils wound on one another. (figure 5)

Secondary Winding Start
Figure 5: Start of Secondary Winding


Complete Windings
Figure 6: Complete Winding




3. In Figure 6 the Complete winding of Primary and Secondary. at tag 1 the two sides of primary side and tag 2 shows secondary side of transformer

4.  At this time it is just two coils with out core. for complete transformer we have to place the iron core.




4. Iron Core:

 1.  It’s time to place core to the transformer. Take two E of laminated iron strips and insert inside the bobbin.(figure 7) Take another two E and place inside but from opposite side as previous. (figure 8) 
Two Es Core Strips
Figure 7: Two laminated E Strips of Iron Core
Two Es in opposite Direction
Figure 8: Two more strips in opposite as previous











2.  Fill the whole place to its mouth leaving no place even for air by doing the same i.e. two E strips from alternate sides. Fill as many as you can do it forcefully.
3.  Now, take two I strips and place between two same direction E s spaces. Fill all the gaps in same manner as E strips were filled having no space.
4.  Use hammer so that the strips sits in proper symmetrical form leaving no space behind and start looking like a single unit of core.


Asad Ullah

I am MSc Electrical Scholar under a fellowship program. Working with Modeling and Simulation software related to my field are my activities in leisure.

What do you think?